To evaluate the impact of ertapenem use in Pseudomonas aeruginosa carbapenem resistance, taking into account the volume of antimicrobial consumption, the consumption by the entire hospital of alcohol-based antiseptic hand rub, and the density rate of invasive practices.

Before-and-after trial.

A tertiary care university hospital in southern Brazil.

Ertapenem was first added to the hospital formulary in June 2006, and it was excluded in February 2009. We evaluated Pseudomonas aeruginosa resistance rates through 3 study periods: period 1, before ertapenem use (17 months); period 2, during ertapenem use (33 months); and period 3, after exclusion of ertapenem (15 months).

After introduction of ertapenem, there was a significant decrease in median consumption of imipenem or meropenem, from 2.6 to 2.2 defined daily doses (DDDs) per 100 patient-days (level change from 0.04 to -1.08; P < .01), and an increase in the use of these medications after ertapenem exclusion, from 2.2 to 3.3 DDDs per 100 patient-days (level change from -0.14 to 0.91; P < .01), by segmented regression analysis. There was no difference in the incidence density of carbapenem-resistant P. aeruginosa infection related to ertapenem use throughout the study periods. However, by multiple regression analysis, the reduction in the rate of carbapenem-resistant P. aeruginosa infection correlated significantly with the increase in the volume of alcohol used as hand sanitizer, which was from 660.7 mL per 100 patient-days in period 1 to 2,955.1 mL per 100 patient-days in period 3 (P = .04). Ertapenem use did not impact the rate of carbapenem-resistant P. aeruginosa infection.

Use of alcohol-based hand gel, rather than ertapenem, was associated with a reduction in the rates of carbapenem-resistant P. aeruginosa infection. Measures to reduce resistance must include factors other than just antimicrobial stewardship programs alone.